Clavicle plate and screws

ABSTRACT

A bone plate and system is provided. The bone fixation plate conforms to the contour of an irregularly shaped bone and eliminates the need for pre-bending or intraoperative bending of the plate. The bone plate is applied to the bone in a generally flat condition and the process of installing and tightening the bone screws in the prescribed order serves to contour the plate to the underlying bone while providing sufficient strength to effect bone healing. The geometry of the plate allows the plate to follow the contour of an irregularly shaped bone, preventing prominence and patient palpability and streamlining the surgical procedure.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The invention relates to bone plates. More particular, the inventionrelates to bone plates and accompanying screws for repairing irregularlyshaped bones such as the clavicle.

2. Description of the Related Art

Clavicle fractures account for approximately 2-5% of all fractures inthe U.S. The majority of these clavicle fractures (approximately 75%)are located in the middle third of the clavicle, a very small percentage(<5%) in the medial third and the remainder in the lateral (or distal)third of the clavicle. Clavicle fractures have traditionally beentreated non-operatively, even when one the fragments is substantiallydisplaced. Clavicular nonunion was thought to be rare and of no clinicalsignificance. Recent studies of displaced midshaft fractures of theclavicle, however, have shown a nonunion rate of 15% as well as a 31%unsatisfactory patient-oriented outcome. These statistics were publishedrecently in the study entitled Nonoperative Treatment Compared withPlate Fixation of Displaced Midshaft Clavicular Fractures. AMulticenter, Randomized Clinical Trial in The Journal of Bone and JointSurgery (JBJS) in January of 2007. The results of the study illustratethat primary fixation using plates is the recommended course of actionfor displaced midshaft clavicular fractures in adult patients.

Another type of clavicle fracture requiring plating occurs when theclavicle is not only broken and displaced but when a second fractureoccurs causing a completely separated fragment. This condition causeseven greater displacement and more patient discomfort and deformity iftreated by non-operative procedures.

The clavicle is an irregularly shaped bone that provides the skeletalsupport for the shoulder. An intact clavicle forces the shoulder outwardand backward. When the clavicle is fractured, muscle and soft tissueforces are now unopposed and this often results in the ends of theclavicle displacing (or telescoping inwardly) and rotating relative toone another as the shoulder drops and rotates forward. These forces makeit difficult to realign (or reduce) a fractured clavicle so that a boneplate can be properly applied. The surgeon must pull the ends apart androtate them back into position and must maintain this reduction whilethe plate is being secured.

The complex shape of the clavicle makes it difficult for a surgeon tobend a flat plate in surgery to match the many contours of the bone. Therelative prominence of the clavicle however, requires that an implantedplate have as low a profile as possible, particularly on the ends whereit transitions to the bone.

Most of the orthopedic plates and screws that have been approved for usein clavicle repair utilize plates designed for use in other areas of thebody and on other bones which have a more uniform shape such as typicallong bones. The typical long bone is characterized as being longer thanit is wide, having a central shaft and two bulky ends and an innermedulary cavity. Bones of the leg, arm, hand and foot are the classicexamples of long bones. These bones have a generally cylindrical shaftwith far less curvature than would be found on a clavicle or a mandible.Plates designed for a typical long bone do not fit the more complexcontours of the clavicle bone and present a number of problems in fixingthe plate to the bone in an acceptable manner. Many of these plates aredifficult to bend in general and are particularly difficult to bend atthe ends of the plate—exactly where precise adaptation to the clavicleis desired. The shape of the clavicle requires the ends of a flat plateto bend and twist in three dimensions for accurate adaptation to thebone surface. The difficulty in doing so with a traditional long boneplate requires an unwanted expenditure of time and effort in theoperating room particularly in light of the difficulty of reducing adisplaced clavicle and maintaining that reduction.

A plate has been designed specifically for the clavicle. It is precurvedin an “S” shape when viewed from above. While this precurvaturegenerally mimics the profile of the clavicle, studies show that thevariability in clavicles results in an inaccurate fit on clavicles inmore than half the cases. Moreover, the study only examined twodimensions and did not account for the curvature and twist of theclavicle surface in the third dimension. The prior art S-shaped clavicleplate is flat in the third dimension and the plate is extremely thickmaking it very hard to bend in order to have the ends follow the surfaceof the clavicle.

Prior art bone plate designs suited for typical long bones includeHuebner (U.S. Pat. No. 6,001,099), which teaches a bone plate withvarying rigidity designed to prevent refracture of a bone adjacent tothe end of the plate. The plate has essentially uniform thickness overthe entire length, with a continuous curvature of the underside thatrelies upon the combination of varying width and spacing between plateholes to produce the desired reduction in stiffness as one moves frommedial to lateral on the plate. Huebner teaches that such plates areparticularly adapted to long bones such as those found in the leg, armhand and foot. The cross-section of his plate is quite similar to thatof Sherman (U.S. Pat. No. 1,105,105) in that it has the “concavo-convexcross section” which produces an increase in strength and stiffness overa generally rectangular cross section of the same width and thickness.While this may be applicable to typical long bones with a generallycylindrical shaft, the plate does not provide the neededthree-dimensional contourability at its ends nor the reduced profilenecessary for a complex and irregular bone such as a clavicle or amandible.

SUMMARY OF THE INVENTION

A bone plate and system is provided. The bone plate and system areparticularly adapted to irregularly shaped bones such as the clavicleand the mandible. The fixation plate conforms to the contour of anirregularly shaped bone and eliminates the need for pre-bending orintraoperative bending of the plate. The bone plate is applied to thebone in a generally flat condition and the process of installing andtightening the bone screws in the prescribed order serves to contour theplate to the underlying bone while providing sufficient strength toeffect bone healing. The plate profile and flexibility reduce patientpalpability, particularly at the ends of the plate which are often themost critical.

The geometry of the plate allows the plate to follow the contour of anirregularly shaped bone, preventing prominence and patient palpabilityand streamlining the surgical procedure. The fragment screws allow theplate to be placed in closer contact with the bone than screws presentlybeing used and the smaller profile of the fragment screws permits easierplacement of the bone screws adjacent to the fracture. The system willprovide a safe method of repairing discontinuities in a bone withcomplex curvature.

The bone plating system includes two or three types of implantabledevices: a bone fixation plate; bone screws; and, fragment screws. Thefragment screws (lag screws) are designed to prevent the plate fromsitting on the head of the fragment screw thereby reducing the profile.The bone screws have an aggressive thread profile that allows the screwto firmly engage the bone and provide the compressive force necessary tobend the plate to the bone and provide secure postoperative fixation.

The bone fixation plate has two ends positioned on opposing sides of theplate. A midsection is disposed between the two ends. The plate has abottom surface and top surface extending from one of the two ends of theplate to the second end. The plate contains one or more holes extendingthrough the plate from the top surface to the bottom. The plate is rigidor stiffer (i.e. less flexible) towards the center of the plate and moreflexible as the plate extends toward the ends. This difference instrength/flexibility along the length of the plate can be achievedthrough a number of different structural configurations. The mainconsideration in the design of the plate is that it be strong enoughnear the center to secure the fracture or discontinuous bone andflexible enough near the ends to conform (bend) to the shape of thebones being plated.

The holes of the plate are shaped on the top surface and sized toreceive bonescrews. The shaped relief at the top of the plate holesallows a fully inserted bone screw to sit in a generally flushrelationship with the top of the plate. The two ends of the plate aresubstantially flat on the bottom surfaces and tapered in thickness. Inone embodiment, the bottom surface of the plate is relieved in themidsection of the plate and the ends of the plate are preferablyscalloped on the edges around the holes.

A method for plating a fractured or otherwise discontinuous bone is alsodescribed. The method includes utilizing the fixation plate and screwsas described herein. The method includes the steps of aligning thediscontinuous bone segments, optionally inserting a fragment screwthrough one segment into the corresponding segment, positioning a boneplate on the aligned bone segments so that the plate extends across thefracture or fractures, driving a bone screw into the bone through a holeclosest to the discontinuity, driving in a second bone screw into thebone through a second hole closest to the discontinuity on the oppositeside of the discontinuity from the first bone screw. Screws are thendriven in the bone through the remaining holes working from the centerto the ends of the plate.

In one embodiment, a plate for irregularly shaped bones is described.The plate has two ends positioned on opposing sides of the plate, amidsection disposed between the two ends, and two or more holesextending through the plate and designed to receive bone screws. The twoends have a different underside profile than the midsection of theplate, and the two ends are thinner than the midsection of the plate.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1 is a top perspective view of a bone plate in accordance with anembodiment of the invention.

FIG. 2 is a is a bottom perspective view of a bone plate in accordancewith an embodiment of the invention

FIG. 3 is a side view of a bone plate in accordance with an embodimentof the invention

FIGS. 4-7 show a top perspective view of different embodiments of thebone plate of the present invention.

FIGS. 8-11 show alternate embodiments of the bone plate of the presentinvention.

FIG. 12 is a perspective view of a preferred bone screw that can be usedto secure the plate to a clavicle.

FIG. 13 is a perspective view of a preferred fragment screw.

FIG. 14 show a top view of bone plate secured to a clavicle bone.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Overview

A bone fixation plate, a bone plating system, and method of plating adiscontinuous bone of irregular shape are disclosed. The bone platingsystem includes two types of implantable devices: a bone fixation plateand bone screws. Optionally the system includes a third type ofimplantable device: fragment screws. As used herein, any reference toplate means bone fixation plate unless otherwise noted. Also as usedherein any reference to screws includes both bone screws and fracturescrews unless otherwise noted. The plate and screws of the platingsystem are especially suitable for midshaft displaced claviclefractures. A midshaft displaced clavicle fracture is a fracture thatoccurs in the middle of the clavicle and one of the bone segments isdisplaced, the two bony ends generally being offset side-to-side andtelescoped end-to-end. This also includes a fracture where there aremore than two segments and one segment may be floating.

In operation the bone plating system is applied as follows. Thestructure of the plate and screws are described in more detail below.After exposing the bone, the bone segments are reduced (aligned) usingbone reduction forceps. A fragment or lag screw or screws may optionallybe used to secure any bone fragments together prior to plating. Thedecision to use fragment screws depends on a number of factors includingthe severity of the fracture but generally, that determination is madeby the surgeon at the time of plating. A fragment screw is applied byinserting (or hereafter alternately referred to as driving) a fragmentscrew through one segment into the other segment. The fragment screw, asdescribed in more detail below, is similar to a lag screw. The distalend threads into the far segment of bone and has clearance in theproximal bone piece. As the tapered end of the screw enters the proximalsegment, the two bone segments are drawn together and the tapered threadtaps into the proximal bone. With only one break, the surgeon may electnot to use a fragment screw and use only a plate and bone screws.

After the fracture is reduced, the surgeon selects the appropriate sizedplate and places a bone screw in one of the holes closest to thefracture and drives the screw into the bone segment. A second screw isplaced on the opposite side of the fracture in the closest hole to thefracture. Screws are then placed in the remaining holes and driven intothe bone working from the center to the ends of the plate. As thesesubsequent lateral screws are placed and tightened, the bone plate endsbend and twist as necessary to meet the irregular curvature of theunderlying bone.

Preferred Embodiments

Referring to FIGS. 1-3, a bone fixation plate 1 (alternatively referredto as bone plate or plate) in an embodiment of the invention is shown.As shown in FIG. 1, the bone fixation plate 1 has two ends 5 a and 5 band a midsection 8 positioned between the two ends 5 a and 5 b. Theplate shown in this embodiment has ten holes. However, the number ofholes can be varied depending on the length of the plate. Preferably,the number of holes ranges from six holes to at least ten holes.

End holes 9 a and 9 b, typically one or two on each end depending on thelength of the plate, are round. Midsection holes 11 are preferablyovular or slotted to allow more variability in screw placement andangulation when placing the screws around the fracture area. The numberof midsection holes 11 varies, preferably from two to six or more. Themidsection holes 11 extend across the length of the midsection 8 of theplate 1. In the embodiment shown in FIGS. 1-2, holes 11 a and 11 b arepositioned on either side of the approximate center 10 of the plate 1with the remaining holes spaced approximately evenly apart and extendingtoward the ends 5 a and 5 b. In alternate embodiments, a midsection hole11 is positioned at or near the center of the plate with the remainingholes approximately evenly spaced towards the ends 5 a and 5 b of theplate 1 (See for example FIGS. 5 and 7). FIGS. 4-7 show alternateembodiments of the plate 1 of varying lengths and corresponding varyingnumber of holes. As is shown, the slotted midsection holes 11 aresubstantially evenly spaced across the length of the midsection 8 of theplate 1 and the ends 5 a and 5 b have 1 or 2 round holes, which may havedifferent spacing than the midsection holes.

Preferably all holes, whether round or slotted, are shaped or enlargedwhere they intersect 14 the top surface 16 of the plate to receive theheads 33 of the bone screws 30 (shown in FIG. 12) and help to reduce theprofile of the implants. Preferably, the plate holes 9 and 11 are sizedand shaped so that the bone screws 30 are substantially flush with orbeneath the top surface 16 (the surface that faces away from the bonewhen applied) of the bone plate 1.

The ends 5 a and 5 b are thinner in thickness as compared to themidsection 8. Preferably the ends taper so that the plate gets thinnermoving away from the center of the plate. This configuration is bestillustrated in FIG. 3 which shows the side 12 or edge 12 of the plate.The thickness of the plate 1 decrease as the plate 1 extends toward theends 5 a and 5 b. However, the decrease in thickness can be abrupt sothat the center of the plate is one thickness and the ends are a secondbut smaller thickness.

As illustrated in FIGS. 1 and 2, plate ends 5 a and 5 b are preferablycircular or radiused at the outer edge 6 a and 6 b of ends 5 a and 5 band scalloped or rounded 7 a and 7 b along the edge 12 of the plate 1around each end hole 9 a and 9 b.

As illustrated in FIG. 2, the underside surface 18 a and 18 b of theplate 1 is flat at the ends 5 a and 5 b in the area of the round holes 9a and 9 b. The underside of the plate 1 has a cylindrical relief 20 inthe midsection 8 in the area of the midsection holes 11. The cylindricalrelief 20 creates two rails 22 a and 22 b at the sides 12 of the plate1. The rails 22 a and 22 b allow the plate 1 to contact the bone betterin the area of the fracture than conventional flat plates. Thisconfiguration also better enables the plate 1 to be drawn more tightlyto the bone (not shown) as the screws (not shown) are tightened.

The configuration of the plate 1, allows the plate to conform to theprofile of an irregularly shaped bone, without having to pre-bend theplate to fit to the curvature of the bone and while still providing thenecessary rigidity for bone healing. The underside radius on the centralsection of the plate allows it to sit tightly against the bone andminimize the plate profile. This underside radius also imparts some ofthe strength advantages but only in a localized area which is designedto span the discontinuity of the bone. FIGS. 8 through 11 show alternateembodiments or configurations that provide the rigid to flexible profileas the plate moves from the center towards the ends. That is, while theembodiments shown in FIGS. 8-11 have different structural features, theyare similar in that they are stronger and less flexible in themidsection of the plate and more flexible towards the ends of the plate,which is the most important to the application of the bone plate to theirregular shaped bone and subsequent healing of the bone. Theembodiments shown herein are just few configurations that can be used;many configurations are possible that achieve this rigid-to-flexibleplate profile. The exact structural configuration to achieve the profileis less important than the presence of the rigid-to-flexible profilealong the length of the plate.

When a bone plate 1 is applied to an irregular shaped bone, the screwsclosest to the discontinuity bear the greatest load. Therefore, theplate bears the greatest load above and directly adjacent to thediscontinuity and this load decreases as one moves outward toward theends of the plate. Toward the ends of the plate 1, strength andstiffness become less important than three-dimensional contourability,particularly on irregularly shaped bones which are not generallycylindrical. For this reason, the underside radius on the centralsection of the plate transitions into a generally flat underside towardthe ends of the plate. This increased three-dimensional flexibilityallows the ends of the plate to bend and twist to meet the underlyingbone surface and this in situ adaptation of the plate to the bone can beaccomplished using only the compressive force of the bone screws.

FIG. 8 illustrates an alternate embodiment of the bone plate. As withthe bone plate 1 described above, the configuration of this bone plateallows the plate 50 to conform to the profile of an irregularly shapedbone, without having to pre-bend the plate to fit to the curvature ofthe bone and while still providing the necessary rigidity for bonehealing. In this embodiment, the scallops 7 extend more medially. Plate50 has similar strength and stiffness between the two center slots orholes 51 a and 51 b but exhibits greater flexibility between all otherslotted midsection plate holes 11.

FIGS. 9A and 9B illustrate another alternate embodiment of the boneplate. Plate 70 is an asymmetric bone plate. FIG. 9A shows a topperspective view and FIG. 9B shows a bottom perspective view. One side72 of the plate 70 has partial or angled scallops 74 positioned betweenslotted holes 11. These scallops 74 remove more material from the bottom75 of the plate 70 than the top 77 although this direction of angulationcould be reversed to remove more material from the top. The oppositeside of the plate has radiused grooves 79 on the top of the plate 70between the slotted midsection holes 11 on the top 77 of the plate 70.Alternately, the slots can be located on the bottom surface of theplate. Both the angled scallops and the perpendicular grooves decreasethe plate cross section between holes thereby increasing the flexibilityof the plate in those areas. In the embodiment shown they are positionedon opposite ends of the plate. The exact number and positioning of thescallops and perpendicular grooves could be altered to achieve thedesired rigidity/flexibility profile of the plate.

FIGS. 10A and 10 B illustrate another alternate embodiment of the boneplate. FIG. 1A shows a top perspective view and FIG. 10B shows a bottomview. In this embodiment the angled scallops 74 are arrangedsymmetrically on the bone plate. The plate has slotted midsection holes11 but those holes could also be round.

FIGS. 11A and 11B illustrate another alternate embodiment of the boneplate. FIG. 11A shows a top perspective view and FIG. 11B shows a bottomperspective view In this embodiment, the midsection holes 11 alternatebetween round shape and slotted shape, while the end holes 9 areslotted. Perpendicular scallops 7 are positioned between all but the twocenter midsection holes 11′. Again this configuration achieves thefunction of having increased flexibility towards the end of the platesand increased strength towards the middle.

FIG. 12 shows a preferred bone screw 30 that is used to secure the boneplate 1 to a bone. The bone screw 30 is preferably in the diameter rangeof 2-6 mm and of sufficient length to provide bicortical purchase. Bonescrew 30 has a shaped head 33 which fits into the shaped countersink 14in the plate 1 to produce a generally flush condition when the screw isfully inserted into the plate. The bone screws 30 of the invention havea deep thread with sufficient pitch to allow the screws to bite into thebone and produce the compressive forces necessary to contour the ends orthe plate to the underlying bone without the risk of stripping thescrews while they are being tightened. Thread depth is measured by thedifference between the outside (or major) diameter D1 of a screw and thecore (or minor) diameter D2. This can be expressed as a ratio.

Major Diameter/Minor Diameter=Thread Depth Ratio

Typically, bone screws for long bones have a cortical thread form with ashallower thread depth which is sufficient for simply clamping apre-bent plate to a bone. These typical long bone screws have ThreadDepth Ratio in the range of about 1.2 to about 1.5. In many cases,however, this thread depth does not permit sufficient thread engagementto allow these screws to reliably bend a plate of the invention to thebone in situ as described above. In the preferred embodiment of the bonescrews 30 used with the bone plate 1 of the invention, the Thread DepthRatio is in the range of 1.5 to 2.0.

FIG. 13 shows a preferred fracture screw 40 that may optionally be usedprior to plating. Fragment screw 40 is approximately 2.5 mm diameter atthe distal threaded end 42 and has a tapered thread 44 at the proximalend 46. Fragment screws may be used in a variety of sizes.

Fragment screw 40 has self tapping threads 42 and 44 that preferablyhave a Thread Depth Ratio in the range of 1.2 to 2.0. This permits itsuse for bi-cortical installation. Fragment screw 40 has a reduceddiameter in the midshaft area 48 of the screw. This configuration allowsthe 2 bone fragments to be drawn tightly together. The tapered thread 44at the proximal end 46 acts as a screw head and draws the fragmentstogether and helps to prevent screw backout.

Additionally, the tapered head 44 gives a smaller profile than a conicalhead and can be drawn down until it is flush or almost flush with thesurface of the bone. This allows the plate 1 to seat more closely to thebone and the smaller size allows the bone screws 30 adjacent to bothsides of the fracture to be placed more easily.

FIG. 14 shows a plate 1 secured to a clavicle bone 80 with bone screws30. The plate 1 conforms to the curvature of the bone 80 without anypre-bending of the plate 1 prior to mounting the plate 1 on the bone 80.The heads 33 of the bone screws 30 do not protrude substantially beyondthe outward facing surface 16 of the plate 1, thereby providing a verylow profile when secured.

The bone plate and its components may be constructed of any suitablebiocompatible material known to have sufficient structural strength anddurability, such as stainless-steel, alloys, cobalt alloys or titaniumalloys, including any suitable ASTM or ISO standard materials as setforth on the United States Food and Drug Administration website, may beused. An exhaustive list is available on the FDA website which alsoprovides the reference numbers and effective dates of the ASTM or ISOstandards for many of the materials that are suitable. Some examplesinclude unalloyed titanium, titanium alloyed with aluminum, niobiumand/or vanadium, stainless steels and other irons alloyed withmolybdenum, chromium, cobalt, tungsten, nickel, manganese in variouscombinations, various other stainless steels or other iron alloys, forexample, with aluminum oxides, zirconium oxides, tantalum and calciumphosphates. Any acceptable polymeric material may be used, such as PEEK(polyetheretherketone), with sufficient flexibility to mimic themicromotion of normal bone, to stimulate bone growth. The PEEK may becombined with other materials or polymers. Also, ceramic filledbiocompatible polymers, or other biocompatible materials of sufficientstrength to stabilize the bone during healing, or correct a fracture ofthe bone may be used to make the bone plate, or any component or memberof the bone plate. Other materials which may be used includebioabsorbable materials and collagen. One or more materials may be usedin building, manufacturing and assembling the bone plates or anycomponent of the bone plates. For example, combinations of the materialsdiscussed herein may be used

The bone plate or any component or member of the bone plate, may furthercomprise bioabsorbable drug delivery devices, such as implantablemodular drug delivery devices. Examples of bioabsorbable drug deliverydevices are described in the co-pending application, U.S. Ser. No.11/135,256 filed May 23, 2005, IMPLANTABLE PROSTHETIC DEVlCES CONTAININGTIMED RELEASE THERAPEUTIC AGENTS, which is incorporated herein in itsentirety by reference. Such devices, for example, may be placed within adedicated bore, such as a drug delivery bore, or within a bone screwbore or locking means bore. Accordingly, the bone plate can be used todeliver drugs, if needed

Bioabsorbable surgical fasteners or bone screws made from bioabsorbablematerials may be used to apply the bone plate, i.e. to apply the firstmember and/or second member, to the bone of a patient. For example, thematerials described in the co-pending patent application, U.S. Ser. No.11/025,231, filed Dec. 29, 2004, SURGICAL FASTENERS AND RELATED IMPLANTDEVICES HAVING BIOABSORBABLE COMPONENTS, which is incorporated herein inits entirety by reference, may be used for the bone screws and the bonescrews may be the surgical fasteners described in this co-pending patentapplication.

There will be various modifications, adjustments, and applications ofthe disclosed invention that will be apparent to those of skill in theart, and the present application is intended to cover such embodiments.Accordingly, while the present invention has been described in thecontext of certain preferred embodiments, it is intended that the fullscope of these be measured by reference to the scope of the followingclaims.

1. A plate for irregularly shaped bones comprising two ends positionedon opposing sides of the plate; a midsection disposed between the twoends; two or more holes extending through the plate and designed toreceive bone screws; wherein the two ends have a different undersideprofile than the midsection of the plate, and the two ends are thinnerthan the midsection of the plate.
 2. The bone plate of claim 1 whereinthe holes are configured on the top surface to receive the heads of bonescrews.
 3. The bone plate of claim 1 wherein the bottom surface has asemi-cylindrical relief in the midsection of the plate.
 4. The boneplate of claim 1 wherein the underside profile of the ends of the plateare substantially flat.
 5. The bone plate of claim 1 wherein the ends ofthe plate are scalloped on the edges around the holes.
 6. The bone plateof claim 4 wherein the ends of the plate are tapered.
 7. A plate systemfor irregularly shaped bones comprising a bone plate; and bone screwssized to secure the plate to a bone and to contour the ends of the plateto the curvature of a bone as they are inserted, wherein the platecomprises two ends positioned on opposing sides of the plate; amidsection disposed between the two ends; and two or more holesextending through the plate and designed to receive bone screws, whereinthe two ends have a different underside profile than the midsection ofthe plater and the two ends are thinner than the midsection of theplate.
 8. The bone plate system of claim 7 wherein the plate holes andscrew head are sized and shaped so that the top of the screw issubstantially flush with the top surface of the plate when the screwsare fully inserted into the holes.
 9. The bone fixation system of claim7 wherein the bottom surface of the bone plate has a semi-cylindricalrelief in the midsection of the plate.
 10. The bone plate system ofclaim 7 wherein the bottom surface is substantially flat at the ends ofthe plate.
 11. The bone plate system of claim 7 further comprisingfragment screws for securing fragments prior to mounting the clavicle.12. The bone plate system of claim 11 wherein the fragment screw has areduced diameter in the midshaft area of the screw.
 13. The bone platesystem of claim 12 wherein the fragment screw has tapered thread at theproximal end.
 14. A method for plating a fractured bone of irregularshape comprising the steps of i) aligning the fractured bone segments;ii) optionally inserting a fragment screw through one or more segmentsinto the corresponding segments; iii) positioning a bone plate on thealigned bone segments so that the plate extends across the fracture orfractures wherein the clavicle bone plate comprises two ends positionedon opposing sides of the plate; a midsection disposed between the twoends; two or more holes extending through the plate and designed toreceive bone screws, wherein the two ends have a different undersideprofile than the midsection of the plate, and the two ends are thinnerthan the midsection of the plate; iv) drive in a bone screw in a holeclosest to the fracture; v) drive in a second bone screw in a secondhole closest to the fracture on the opposite side of the fracture fromthe first bone screw; vi) repeat step iv) and v) for the remaining holesin the plate, proceeding from medial to lateral, thereby fixating thefracture and shaping the ends of the plate to the curvature of the bone.15. The method for plating a fractured bone of irregular shape of claim14 wherein the holes of the fixation plate are sized and shaped so thatthe top of the screw is substantially flush with the top surface of theplate when the screws are fully inserted into the holes.
 16. The methodfor plating a fractured bone of irregular shape of claim 14 wherein thebottom surface of the bone fixation plate has a semi-cylindrical reliefin the midsection of the plate.
 17. The method for plating a fracturedbone of irregular shape of claim 14 wherein the ends of the bonefixation plate are scalloped on the edges around the holes.
 18. Themethod for plating a fractured bone of irregular shape of claim 14wherein the ends of the plate are tapered.
 19. A plate for irregularlyshaped bones comprising two ends positioned on opposing sides of theplate; a midsection disposed between the two ends; two or more holesextending through the midsection of the plate and sized to receive bonescrews; one or more holes extending through each end of the plate;wherein the ends of the plate have a greater degree of flexibility thanthe midsection of the plate.
 20. The plate of claim 19 wherein thegreater degree of flexibility is achieved by the two ends having adifferent underside profile than the midsection of the plate, and thetwo ends being thinner than the midsection of the plate.
 21. The plateof claim 20 wherein the underside of the ends of the plate aresubstantially flat and the underside of the midsection has asemi-cylindrical relief.
 22. The plate of claim 19 wherein the greaterdegree of flexibility is achieved by scallop edges on the plate aroundthe holes on the ends of the plate.
 23. The plate of claim 19 whereinthe greater degree of flexibility is achieved by radiused groovesbetween the holes on the ends of the plate.